Young people remain disproportionately affected by HIV. School-based prevention programs, such as Reducing the Risk (RTR), have demonstrated effectiveness in reducing the sexual risk-taking behaviors associated with HIV transmission. School settings are an important venue for reaching adolescents nationwide with effective prevention education, and most states have policies requiring sexuality and/or HIV education in schools. RTR is a widely used HIV prevention program - potentially the most widely used in US schools - with multiple replication studies finding positive changes in youth outcomes. However, RTR's length (17 hours of class time) challenges educators who replicate it, it does not employ modern (let alone innovative) use of digital technology, nor does it address current trends in digitally-based sexual pressure. A modernized delivery model is needed that capitalizes on recent trends, such as the flipped classroom blended learning model and technological advances (e.g., Web 2.0 tools) that may enhance students' motivation and perceived relevancy, yielding stronger and more lasting impact. The proposed study aims to address these challenges/needs by establishing the technical merit and feasibility of producing and using a blended learning version of RTR for 14-18 year olds. The Blended RTR (BRTR) prototype will use a flipped classroom blended learning approach and include traditional RTR classroom-based activities and new transposed online activities (eRTR activities) to be completed by youth as required homework, outside of the classroom. The Phase I project will develop the BRTR prototype for the first 8 RTR sessions with interfaces for teachers and students. The prototype's usability and acceptability will be piloted and assessed with approximately 5-8 teachers and 100-150 students. The general feasibility indicators for pilot testing teachers and students are:1) Teachers implement BRTR as designed, find it easy to use and scalable for other schools and would recommend BRTR to others; 2) students find eRTR activities easy to use, engaging, and the content relevant and understandable and a majority would (or did) recommend BRTR to friends; 3) students show positive changes in their levels of knowledge, attitudes, and intentions regarding sexual activity from pretest to posttest; and 4) a majority of youth complete the majority of eRTR activities as assigned. The results of this project will inform a future Phase II proposal that will aim to produce and evaluate the effectiveness (with a randomized controlled trial) of the full BRTR curriculum to engage youth in an evidence-based intervention and reduce their sexual risk-taking behavior.